STIs overview

Had unprotected sex?

Sex without using a condom can put you at greater risk of getting a sexually transmitted infection. On this page you can find general information about STIs including symptoms, testing and treatment. 

Sex without using contraception can put you at risk of pregnancy at any time during the menstrual cycle. You can use emergency contraception up to five days after unprotected sex. Emergency contraception is more effective at preventing pregnancy the earlier it is used.

STIs overview

Some infections can pass to another person through unprotected vaginal, anal or oral sex, by genital contact and through sharing sex toys. Infections spread in this way are known as sexually transmitted infections.

Safer sex involves using condoms correctly every time you have sex. If you don’t use a condom you are more at risk of getting a sexually transmitted infection.

You don’t need to have lots of sexual partners to get an infection.

  • Use male or female condoms every time you have vaginal or anal sex.
  • If you have oral sex, cover the penis with a condom or the female genitals and male or female anus with a latex or polyurethane square.
  • If you are not sure how to use condoms correctly see our information on external condoms and internal condoms.
  • Avoid sharing sex toys. If you do share them, wash them or cover them with a new condom before anyone else uses them.

Most sexually transmitted infections can be treated and it is usually best if treatment is started as soon as possible.

Some infections, such as HIV, genital warts and genital herpes, never leave the body but there are drugs available that can reduce the symptoms. Drugs can also help prevent or delay the development of complications in HIV.

If left untreated, many sexually transmitted infections can be painful or uncomfortable, and can permanently damage your health and fertility, and can be passed on to someone else.

Not everyone who has a sexually transmitted infection has signs and/or symptoms. Sometimes these don’t appear for weeks or months and sometimes they go away, but you can still have the infection and pass it on to someone else.

If you experience any of the following you should seek advice:

  • unusual discharge from the vagina
  • discharge from the penis
  • pain or burning when you pass urine
  • itches, rashes, lumps or blisters around the genitals or anus
  • pain and/or bleeding during sex
  • bleeding between periods (including women who are using hormonal contraception)
  • bleeding after sex
  • pain in the testicles
  • pain in the lower abdomen.

You can get all tests and treatments at a GUM or sexual health clinic. General practices, contraception clinics, young people’s services and some pharmacies may also provide testing for some infections. If they can’t provide what you need, they will be able to give you details of the nearest service that can.

All advice, information and tests are free, but if you go to a general practice you may have to pay a prescription charge for any treatment.

Tests for both men and women may include:

  • an examination of your genitals, mouth, anus and skin to look for obvious signs of infection
  • testing a sample of your urine
  • having blood taken
  • taking swabs from the urethra (tube where you urinate) and any sores or blisters
  • taking swabs from the throat and the rectum. This is less common.

In women the tests might also include:

  • taking swabs from the vagina and cervix (entrance to the uterus)
  • having an internal examination.

You will not automatically be tested for all infections. All tests are optional and should only be done with your permission. Sometimes you will get the results straightaway, and sometimes you will have to wait. The service will explain how you will get the results.

If you think you might have a sexually transmitted infection (STI) but don’t have any signs or symptoms, a home test can be a convenient way to get tested for STIs such as chlamydia, gonorrhoea, syphilis and HIV.

If you have signs or symptoms of an STI it is best to go to a clinic, GP or other service to be tested in person.

In some areas you can order a free home testing kit (see Where else can I get help?).

You can also buy home testing kits in some pharmacies and online from trusted pharmacy websites and specialist testing websites.

All home tests should carry a CE mark and be licenced for use in the UK. Do not buy or use a test without a CE mark as it may not give an accurate result.

Make sure your kit is sealed, undamaged and has not passed its expiry date.

Home testing kits are only accurate when used according to instructions, however, no kit is 100% accurate. If you are unsure about your result, ask the testing service for advice or get advice from your local clinic or sexual health service.


Self-sampling tests

Testing at home usually involves taking your own sample (self-sampling) and sending it back to the service to be tested. Depending on which STIs you are testing for you might need to provide a blood sample, a urine sample, a swab from the vagina (for women), or a swab from the anus or mouth. You will get instructions to help you do this.

The service will contact you with the results and advise you whether any treatment is needed and whether you also need to visit a clinic in person.

If you buy a test you may also need to pay for any treatment. The service should also offer you support, or tell you where to get support if you need it, for example if you feel upset or angry about having an STI.


Self-testing for HIV

You can buy an HIV home test online which can give you your result within around 15 minutes. This involves taking a blood sample and testing it yourself.

The test result will be either negative (no HIV antibodies detected) or reactive (HIV antibodies detected). A reactive result is sometimes called a positive result but this does not necessarily mean you are HIV positive. If you have a reactive result you will need to have another test at a clinic or other service to confirm the result.

If you choose to use a self-test it’s important to think about how you might feel and what support you might need if your test is reactive.

If you have become HIV positive in the last three months a self-test might not be able to detect the infection. If you think you have been exposed to HIV in the last three months then get a test at a clinic, GP or other testing service.

Other services available may include:

  • sessions for people who have been sexually assaulted
  • psychosexual counselling (to help with sexual problems)
  • hepatitis B vaccination
  • post-exposure prophylaxis (PEP) – a short course of anti-HIV drugs for people who may have recently come into contact with HIV.

Wherever you go, you shouldn’t be judged because of your sexual behaviour.

  • All advice, information and tests are free.
  • All services are confidential.
  • All tests are optional and should only be done with your permission.
  • Ask as many questions as you need to – and make sure you get answers you understand.
  • The staff will offer you as much support as you need, particularly if you need help on how to tell a partner.
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This website can only give you general information about sexually transmitted infections. The information is based on evidence-based guidance produced by The British Association for Sexual Health and HIV (BASHH) and the National Institute for Health and Care Excellence (NICE).

Remember – contact your doctor, practice nurse or a clinic if you are worried or unsure about anything.